Added a more robust test for nested quotes in attributes
Added a more robust test for nested quotes in attributes

HossainKhademian/HtmlMinifier,jonnochoo/html-minifier,kangax/html-lint,GerHobbelt/html-minifier,psychoss/html-minifier,bryanerayner/html-minifier,kangax/html-minifier,kangax/html-minifier,DChristiany/html-minifier,bryanerayner/html-minifier,MacManus/html-minifier,AshKyd/html-minifier,AshKyd/html-minifier,DChristiany/html-minifier,kangax/html-lint,GerHobbelt/html-minifier,MacManus/html-minifier,jonnochoo/html-minifier,psychoss/html-minifier